Tooth.



A. M. KAEHR.

Patented Oct, 14, i913.

ua mw ARTHUR MJKAEHR, OIF DUBUQUE, IOWA, ASSIGNOR 0F ONE-HALF 1.0 FRANK MINDORFEB, 0F DUBUQUE, IOWA.

' TOOTH.

Specification of Letters Patent.

PatentedOct. 14, 1913.

T o all whom t may concern.'

Be it known that I, ARTHUR M. KAEHR, a citizen of the United States, residing at Dubuque, in the county of Dubuque and State of Iowa,l have invented certain new and useful Improvements in Teeth, of which the following is a specication.

My invention relates to dentistry with special reference to bridge and crown work and the object is to provide a facing for a false tooth equally as suitable for bridge work as for crown work that shall not show any of the metal and the upper incisal thirdof the tooth shall have no metal backing but shall be substantially as strong and have the exact appearance of the original tooth it takes the place of, and shall .also be translucent.

Another object is to make the facing of such construction as to make possible the narrowing or thinning of the finished tooth which is (frequently necessary in crown or bridge construction) without weakening the existing support 4between the` facing and backing and also permit of the removal of the facing from the backing duringthe pro'cess of uniting the various backings of teeth in the bridge runder construction.

A further object of my invention is to unite or lock the facing to the metal back-l ing in such a manner, that it will resist all strain between facing and backingto which the facing is subjected in use and if the facing becomes broken it can be replaced without .removing the bridge.

In what my invention consists, the mode of construction and manner by which I accomplished these objects and others associated therewith, will be fully set out in the following specication when viewed with relation to the drawings accompanying the same and forming a part hereof.

Figure 1 is a .perspective view of the completed tooth. Fig. 2 is a side elevation of the parts before they are united together. Fig. 3 shows a vertical section through the center of Fig. 1. Fig. 4 is a perspective view of the facing taken from the back side. Fig. 5 is a perspective view of the backing with the facing removed. Fig. 6 is a vertical section through lines X-X of Figs. 4 and 5 when united together with the pins inserted into the backing and into the openings in the facing.

Like characters of 'references denote corresponding parts in each of the gures.

In the construction of false teeth the thought has been to so construct the tooth, that it shall appear anatomically correct and as -near to the natural tooth in appearance as the original tooth it is designed to take the place of. It should not only look like the real tooth but should be as strong as the tooth it displaces. In order to accomplish this the enamel or porcelain facing should completely hide from view .the metal backing and all of the incisal third or chewing surface of the tooth should project above the backing in the form of a real, strong, translucent tooth, and such facing should be so united to the backing .that it will not become displaced or crack even under extraordinary hard usage and if it should become broken or injured it may readily be replaced without removing the bridge.

Referring to the drawlngs 2 designates the backing, which is made of metal, referably of gold, and in the base of which is secured the usual post 4 that is inserted in the root of the tooth 3. This backing is curved out at 5 similar to the bulge'of an ordinary front tooth. At the opposite side near the top it is formed into bevel or slanting shape at 6 and then in a vertical plane at 8 to near the lower end and terminates in a triangular shape at 10. The triangle 10 is provided with a recess in its lower =end .adapted t0 be engaged, by a lug or pin in the hacking.

The facing l5 is formed of enamel or Iporcelain and of the same outer contour as the natural tooth with the incisal third or chewing surface 18 of the same size and shape as the tooth and extending down to the backing at 20 as shown in Figs. 3 and 6. It will be noticed that the metal backing does not extend up to the chewing surface but only to the incisal third or far enough to avoid interfering with theV translucency of the same and still the tooth is of the same size and as strong at the upper part as the natural tooth. From 20 it follows the shape-- of the backing having the slantng fface 22 and vertical face 24 and projecting slightly over the backin at the lowerl end where there is provide .a .rim 23, then at the bottom it is provided with a recess 25 adapted v to be engaged by a lug l2 on the backing 2.

For the purpose of strengthening the tooth and securly .holding the facing on the backing with the upper portion of the tooth extending above the backingand concealing all of the bacln'ng from the front View of the tooth, the sides of the lower rear part of the facing are provided with two outside reinforcements 26 having their outer ed es slightly beveled outwardly at 28 and midway between the reinforcements is another reinforcement 30 which is made in wedge shape. Between the reinforcements 26 and the reinforcement 30 are two recesses 31 and in the upper end are two verticall disposed openings 32 that extend upwar into the facing toward `the chewing edge, as shown in Figs. 1, 3 and 6. These openings are inA a plane parallel to the post 4 and of the coinpleted tooth. As a further means for holdmg the facin on the backing the lug 12 connected to t e backing is inserted in the recess 25 in the facing and cemented therein. This construction will prevent the facing from any movement away from the backing, even if a strong anterior ressure is brought against Vthe incisal thir or chewin surface 18.

he backin 2 has upon each inner side two beveled epressions or recesses 34 into which the beveled reinforcements 26 snugly fit; also a central recess or groove 35 and etween the recesses 34 and 35 are two reinforcements or raised ortions 36` that are so formed as to fit close y into the recesses 31 in the facin In the reforcements 36 are set two hea less pins 38 which are so set that they are adapted to engage the openings 32 in the facing; These pins are set in a lane parallelv wit the post 4, or parallel with the finished tooth. It is manifest that the ins may be first Set in the openings 32 in the facin instead of in the backin as shown, or, t e pins may not be secured in either the backi or'facing but secured in both when unite together. I do not limit myself to ori inally setting the pins in the facing or bac ing but only as may be most convenient. yIn order to be able to remove or replace a broken facing without removing the bridge, the pins are headless and are of uniform size and are cemented in the 'casing and the backing instead vof the usual mode of baking them into the facin so that all that is necessary to replace a acing is simply to remove the brokenone and set the new acing on the pins in the openin in the facing and cement them therein. st is manifest that by this mode of construction and assembling with the pins vertically disposed and embedded in the facing and backing and the lug in the baseof the facing, that with any use of the tooth the facinwill not become displaced and the tooth will be exceedin ly strong. Further by having the incisal thir above the backing and secured in the manner set forth, the tooth may be of the exact size and shape of the tooth it takes the place of and will also be translucent and no backing will be in evidence.

or chewing surface 18 project immers i Having now described my invention what I claim 1s:-.

1. In a device of the character described, a facing projecting above and concealing the backing and provided with openings set into the facing above the backing and 1n a plane substantially parallel with the long axis of the tooth when fixed in position, said openings adapted to be engaged by-headless pins of uniform size in the backin 2. Ina device of the character described a facing provided with vertically disposed openings, extendin into the incisalthird of the tooth and a apted to be engaged by vertically disposed ins, means connected with the backing and) adapted to engage the facing and for preventing the facing from becoming disengaged from thebacking at the neck of the tooth.

3. In a device ofthe character described, a backing, headless pins of. uniform size throughout secured in the backing and projecting therefrom in substantially a` vertical plane, in combination with the facin provided with openin s set in substantie y the same plane 'and a apted to be engaged by the ins in the backing, said facing set upon the acking with the incisal third thereof extending above the backin and means secured in the backing and a apted to engage the facing at the base and hold the facing from any movement away from the backin 4. In a device of the character described, a facing set on a backing with its incisal third of the facin extending above the backing and provide with vertically disposed openings extending up into said incisal third beyond the backing, and said facing provided with an opening in. its base, in combination with a backing provided with vertically disposed openings in substantiall the same vertical plane and registering wit the openings in t-hc facing, ins set in the openings in the backing and) adapted to engage the openin s in the facin and be secured therein, an a lug secured to the backing and adapted to engage and be secured in the opening in the base of the facing.

5. In a device of the character described a facing provided with vertically disposed openings, reinforcements on the rear of the facing, in combination with a backing provided with vertically disposed openings, reinforcements on the backing adapted to engage the facing between the reinforcements therein, and a plurality of pins adapted to be secured in the openings in the facing and backing and hold them together.

'6. In a device of the character described, a backing, reinforcements set a short distance apart in the backing and each rein'- forcement provided with a vertically disposed opening extending into the backing, in combination with a facing having its incisal third projecting above the backing, re-

inforcements secured to the rear of the backing a short distance apart With vertically disposed openings between the reinforcements and extending up into the incisal third of the casing, said openings adapted to register with the openings in reinforcements of the backing, and pins adapted to be secured in' the openings in the facing and backing.

7. In a device of the character described, a facing adapted to project above the backing, said facing provided with an opening in its base, a plurality of reinforcements secured in the back of the facing with a space between the reinforcements, and said facing provided with openings entering the incisal third of the tooth between the reinforcements and extending in a plane parallel with the ,long axis of the toothin combination with a backing provided with reinforcements adapted to register With the recesses between the reinforcements on the facing, and said reinforcements provided With openings set yparallel with the aXis of the tooth and. registering with the openings in the facing, a lug on the backing adapted to engage the opening in the base of the facing and be secured therein, and pins secured in the openings in the backing and facing.

In testimony whereof I aix my signature in presence of two Witnesses.

ARTHUR M. KAEHR.

Witnesses v M. M. CADY, B. M. HENSCHEL. 

